Efficiency improvement analysis of nano-patterned sapphire substrates and semi-transparent superlattice contact layer in UVC light-emitting diodes

Chia Yen Huang*, Chia Lung Tsai, Cheng Yao Huang, Rong Yu Yang, Yewchung Sermon Wu, Hung Wei Yen, Yi Keng Fu

*此作品的通信作者

研究成果: Article同行評審

4 引文 斯高帕斯(Scopus)

摘要

UVC light-emitting diodes (LEDs, λ = 275 nm) with different types of contact layers and sapphire substrates were demonstrated on high-quality AlN templates. For LEDs on flat sapphire substrates (FSSs), replacing the absorbing p-GaN contact with p-AlGaN short-period superlattices (p-SPSLs) strongly enhanced the emission along the substrate normal. The integrated external quantum efficiency (EQE) increased from 2.4% to 3.9% under I = 350 mA. For LEDs with a p-SPSL contact, replacing the FSS with nano-patterned sapphire substrates slightly deteriorated the quality of epitaxy, but the overall EQE is still enhanced to 4.4% under I > 350 mA without lens encapsulation. According to the far-field intensity measurement, the light extraction is better improved along the high emission angle to the substrate normal. The interplay among substrates, dipole polarization, and EQE enhancement factors was further analyzed and discussed in the context.

原文English
文章編號261102
期刊Applied Physics Letters
117
發行號26
DOIs
出版狀態Published - 28 12月 2020

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